Filter



(No Model.)

' E. M. KNIGHT.

FILTER.

2 Sheets-Sheet 1.

Patented Jan. 27,1891.

"me Nunma PETERS cm. muro'u'mo wAsmNaTon, n. c,

(No Model.) 2 S11eetsSheet 2. E. M. KNIGHT.

NITED STATES PATENT OFFICE.

EDlVARD ML KNIGHT, OF SAN FRANCISCO, CALIFORNIA.

FILTER.

SPECIFICATION forming part of Letters Patent No. 445,223, dated January27', 1891.

Application filed May 8, 1890, Serial No. 351,069. (No model.)

To all whom, it may concern:

Be it known that I, EDWARD M. KNIGHT, a citizen of the United States,residing in the city and county of San Francisco, State of California,have invented an Improvementin Filters; and I hereby declare thefollowing to be a full, clear, and exact description of the same.

My invention relates to that class of filters in which a fibrous orporous material is employed to support the filtering medium; and itconsists in certain devices and details of construction, which will bemore fully described hereinafter.

Referring to the accompanying drawings for a more complete explanationof my invention, Figure 1 is a view of one of my filter sides. Fig. 2 isa view of the frame of the same. Fig. 3 is front view of the outer tankor casing partly broken away, showing the interior arrangement of thedifferent parts. Fig. 4 is a lateral vertical cross-section through thecasing, and also one of the filter-sections.

In my former patent, dated January 14, 1890, No. 419,266, I have shown afibrous surface to support the filtering medium stretched over aninterior frame-work and an exterior cover of wire screen-work which isdesigned to uphold the filtering medium which is applied to the outsideof the fibrous covering. In practice I have found that it is impossibleto stretch the fibrous covering sufficiently tight to prevent itssagging away from the exterior screen, and this allows the filteringmedium, which is composed of a charcoal paste, to peel and fall off fromthe fibrous covering.

In my present invention I apply a backing of wire-cloth orfinely-perforated sheet metal, over which the fibrous material isstretched and secured by a device to be hereinafter de scribed.

The filtering medium, being spread upon a fibrous material, forms afilterbed which will remain intact on account of the rigid supportbehind the fibrous material, and the screen itself is also supportedfrom the interior by a certain arrangement of cross pieces or braceswithin the filter-frame.

I11 my present invention, A is the filterframe, which is made of anysuitable material; but I prefer to make it of sufficientlyheavy sheetmetal, and 13 3 are diagonallyarranged bracing-pieces extending from thecorners of the exterior frame toward the center, perforated so as toallow a free circulation of water through all parts of the interior ofthe frame; These strips B are as wide as the depth of the filter fromside to side, so that when the filtering sides are secured upon thesides of the frame A they will be supported by the edges of thesebracing-strips.

The sides of my filter are formed of wirecloth, finelyperforated sheetmetal, or in some cases a fine lattice-work of anysuitable material D,having the ends projecting and forming prongs D, as shown in Fig. 1, andupon this is spread the fibrous material E, which is designed to supportthe filter-bed F. This fibrous material I have preferably shown made ofasbestus, as being the most durable, and its edges are passed over andpartially held by the prongs of the lattice-work D, as shown in Fig. 1,and the filter-bed comprises a coating of finely-pulverized charcoal,which is applied by mixing it with water, so as to form a paste, whichis afterward brushed upon and into the fibers of the cloth until asufficient thickness has been applied. The water percolates through thisfilter-bed of charcoal paste and through the cloth and the wire screeninto the interior of the chamber formed by these filtering sides and thesupporting-frame A.

In order to secure the fibrous material to the wire or other screen orsupport, I have shown metal plates folded so as to fit over the edges ofthe screen, and the fibrous material or cloth is made sufficientlylarger than the screen so that it folds over the ends and sides of thescreen. These folded metal strips G are then pressed on over these edgesand are afterward soldered or otherwise secured to gether at theirmeeting angles, and suit-ably braced by re-euforcing corner-pieces,which also prevent leakage at the angles, thus securing the fibrousmaterial so that it forms a smooth and unyielding surface, upon theexteriorof which the filter-bed is applied, as pre' viously described.The folded plates which form the surrounding edges of the filteringsides are then soldered or otherwise hermetically secured upon the edgesof the frame A,

and the diagonal bracing-pieces B support the central portions of thescreen-surface upon which the cloth is strctchechthus preventing thescreen from being bent inwayd by the pressure of water upon it, and thescreen in turn prevents any inward sagging of the fibrous cloth. This isimportant, because if any sagging of this kind should take place thepaste or filter-bed which is applied to the cloth will fall off, andthus impair the efficiency of the filter. By this construction I amenabled to entirely dispense with any outer covering or support for thefilter medium, and it enables me at all times to easily cleanse thefiltering-surface or replace the filter bed upon it.

Another importantfeature in my invention is the manner of securing theedges of the cloth or fibrous material so as to form a wa- 2o ter-tightjoint around these edges and prevent any leakage of unfiltered waterthrough this joint.

This filter-frame is contained within an outer casing or chamber H, andthe filterframe has a tubular stay I, passing through its top, bottom,and also through the interior bracing-strips B, to which it is secured.It is also secured to the top and bottom of the filter-frame by flangesor collars, so that when 3 the filter is lifted by the tube I it isperfectly rigid and the bottom cannot sag. The extension of the tube Iat the bottom has a suitably-formed ground-rubber or other watertightjoint I, which connects with the pipedeliveringintothereservoir-chamberbeneath,

which isa-dapted to contain the filtered water. This pipe I isperforated inside of the case A, so that the filtered water which hasflowed into this case through the filtering 40 sides may pass throughthese perforations and thence down through the pipe into the reservoiror discharge-pipe, as the case may be.

In order to prevent the filterframe from rising up within the exteriorcase, I have shown two parallel-strips J, fixed across the upper part ofthe exterior case, and between these the upper end of the tubular staypasses. A nut or screw K is fixed to turn upon the threaded portion atthe upper end of the tube I, and after the filter-frame is in place andthe joint I properly connected at the bottom this nut is turned upagainst the cross strips or pieces J, and thus holds the frame in place,preventing it from rising. The filter-frame is easily removed byloosening the nut K and disengaging the pipe I from the joint at thebottom. The upper end of this tube serves to admit air into the interiorof the filterframe by means of holes L, made in the tube oradjusting-collar just beneath the upper side of the filter-frame, and asthe water passes down into the reservoirbenea'th through the holes whichare made in the lower part or near the bottom of the filter-frame itwill be manifest that the air will be caused to circulate through thistube, and will sufficiently aerate the water which has been filtered.

I prefer to construct the unfiltered water reservoir or exterior easing,into which the filter-frame is introduced, of iron, and the reservoirforcontain ing the filtered waterI preferably makeof tinned copper; butas this has not a great amount of rigidity to resist internal pressure Ihave shown a truss or bracing of steel or, iron plates M, covered withtinned copper, made of sufficient thickness to keep the top and sides ofthe reservoir in their proper position and to resist any pressure whichmay be brought upon the com paratively soft metal of the reservoirandwhich it is not stiff enough to resist. By thus separating the casingwhich contains the unfiltered water from the reservoir of the filteredwater and uniting them, as shown, any leakage in the former will passdown outside of the filtered-water reservoir and not contaminate itscontents. I am also enabled to make the unfiltered water tank ofgalvanized iron, which is inexpensive, and the filteredwater reservoironly need be made of the more expensive tinned copper.

By means of the truss plates or supports for the ground joints I preventthe reservoir from sagging or changing shape, and thus insure a perfectjoint where the pipe I delivers water from the filter to the reservoir,and prevent leakage without a resort to screw or other connections whichare more difficultto uncouple.

The water may be admitted into the case which contains the filter-frameeither from the top or the bottom. In either case it is desirable toprevent the water from flowing in in such a manner as to create currentswithin the chamber, and thus disturb the filter-bed and wash it off.WVhen the wateris admitted from the top, it may be done by means of acock N, having the ordinary float or ball 0 connected with thelever-arm, so as to cutoff the supply by closing the cock when asufficient amount. of waterhas been admitted into the exterior chamber.From the mouth of the cock I have shown directing-plates P, which are soarranged as to receive the water as it flows from the cock, and todeliver it against the sides of the chamber so that it will fiow downgently and easily and without any splash, which would disturb the waterand make it liable to wash off the filter-bed.

In order to render the sides of' the sheetmetal vessel which containsthe filter-frame sufficiently stiff to support the ball-cock N and toallow the movement of the cock by the rise and fall of the float withouttwisting or bending the side of the chamber, I have shown there-enforcing plate Rsoldered or otherwise secured to the side of theVessel under the ball-cock, thus imparting as much rigidity to thevessel at this point as will enable it to withstand the twistingpressure caused by the rising and falling of the ball, and as the sideis thus prevented from yielding it will insure the cock acting perfectlyso as to cut off the supply of water and prevent a con- IIO stantleaking, which might otherwise occur, or the necessity for making thevessel of very much heavier material.

For the purpose of lessening the cost of manufacture, to facilitate thecleansing of the filter and renewal of the filter-bed, to increase thecapacity, and to detect and locate leakages, I have shown in Figs. 3and4 an exterior case adapted to contain two or more filteringframes,each constructed as previously described and adapted to fit within theexterior case side by side, where they are held in place by the tubularstays I, and each of the pipes through which the filtered water escapesat the bottom is fitted into a grou nd-j oint, which joint is supportedby therigid iron or metal bar fitted into the sides and top of thereservoirtank and having a direct bearing thereon, and this gives greatstability and rigidity to these joints, insures their remaining tight,and prevents leakage of unfiltered water from the case holding the sameinto the filteredwater reservoir.

In order to inspect the interior of the reservoir at any time when thewater has been drawn off, I have shown a large screw cap or cover S,fitted into one end of the reservoir, preferably by screwing into a ringor flange which is fixed into the end of the reservoir. hen this isremoved, the interior of the reservoir is easily reached and inspected,and if it has been discovered that the water from the reservoir is inany way contaminated I am enabled by removing this cover to detect anyleakage from the tanks above, and by collecting a portion of the waterdelivered from each one in a glass I can at once determine which of thefilters in the case above is delivering impure water. This may then beremoved after discharging the water from the tank and the errorrectified without disturbing any of the other filtering-frames.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. Afilter consisting of asbestus cloth or other fibrous material, anexterior coating of filtering medium spread upon the cloth, and aninterior rigid supporting-screen over which the fibrous material isstretched and by which it is prevented from sagging, said innersupporting-screen having projecting prongs over which the edges of thefibrous material are passed, whereby said material is secured,substantially as herein described.

2. In a filter, the foraminousplate or screen forming an interior rigidsupport for the filter-bed, a filter-bed composed of asbestus cloth orother fibrous material stretched over the exterior of the screen andhaving the edges projecting and folded over the edges of the screen, andfolded metal plates adapted to clasp the edges of the cloth and thescreen, said plates being soldered or secured So as to retain the screenand cloth and form a tight joint between the edges thereof,substantially as herein described.

3. A filter consisting of asbestus cloth or other fibrous material andan exterior coating of filtering medium in the form of paste spread uponthe cloth, a rigid interior screen forming a back or support for thefilter-bed, over the edges of which the cloth is folded, clan'ipingstrips fitting over the folded edges of the cloth and soldered orsecured so as to retain it stretched over the screen, and supplementalcorner pieces or plates fitted upon the angles of the filter-frame,substantially as herein described.

4. In a filter, the exterior frame having the filtering sides, thesupporting-screens, and the diagonal plates upon which the screens rest,in combination with the tubular stay extending vertically through thefilterframe and diagonal plates and having the adjustingcollars, wherebythe stay is connected with both top and bottom of the frame and thecentral plates, so that the filter-frame may be lifted without twistingit out of shape, substantially as herein described.

5. In a filter, the filter-frame having the diagonal and perforatedbracing-plates, the sides formed of screens supported upon the edges ofthe interior plates and hermetically secured to the edges of the frame,a fibrous filter-bed stretched over said screen, having its edgessecured thereto, and a coating of filtering material applied to theexterior of the fibrous cloth in the form of a paste, in combinationwith an exterior casing for containing unfiltered water within which thefilter-frame is submerged, and a'tubularstay extending through thefilter-frame from top to bottom, having perforations in the lower partwithin the filter-frame, through which water may flow from the interiorof the filterframe into the tube, a ground or rubber joint exterior tothe lower part of the filter-frame,-

through which the filtered water passes out, and a transverse bracefixed across the upper part of the casing and having a locking devicewhich engages the upper end of the tubular stay, whereby thefilter-frame is prevented from rising and the joint at the lower end iskept tight, substantially as herein described.

6. A filter consisting of an exterior casing, one or more filter-frameshaving the filtering sides, interior screen-supports for said sides, andthe plates upon which the screens are supported, a tubular stayextending through each of the filters, having a ground or rubber jointat the lower end, by which connection is made with the reservoir orreceiver of the filtered water, openings in said tube near the bottomand interior of the filter frame, through which water escapes therefrominto the tube, and openings in the upper part within the filter-frame,through which air may be admitted from the upper end of the tube toaerate the filtered water, a transverse brace fixed in the upper part ofthe exterior casing, and adjusting nuts or collars fitted upon thetubular stay, so as to engage the brace and hold the filtenframes inplace within the easing, substantially as herein described.

7. A filter consisting of an exterior casing, one or more filter-frameshaving the filtering 5 sides through which the Water passes from theexterior casing to the interior of the filter-frames, and a pipe orpassage through which the Water escapes from the interior of saidfilter-frames, in combination Witha res- IO ervoir into which said pipesdeliver the filtered water, a ground or rubber joint between theunfiltered and filtered water reservoirs, and a strengthening stay orsupport within the filtered-Water reservoir, upon which the ground-jointis fixed and supported, substan- I5 tially as herein described. 7

In witness whereof I have hereunto set my hand.

EDWARD M. KNIGHT. Witnesses:

S. H. NOURSE, H. 0. LEE.

